Quick connectors are used widely, for example, for connecting fuel tubes of automotive fuel systems. The quick connector is capable of simply and quickly connecting tubes without using any fastening means, such as bolts. The quick connector has a connector body to be attached to one of two tubes, and a retainer to be pressed in the connector body after inserting the other tube in the connector body to retain the tube in the coupling body. Representative quick connectors are disclosed in Patent documents 1 and 2.
As shown in FIG. 8, one of two tubes to be connected by a quick connector of this type, namely, a tube 2 in FIG. 8, is provided with an annular ridge in its end part. A sliding retainer 5 is pressed radially into a connector body 4 through an opening formed in the connector body 4 so that and end 6a of a rib 6 formed in the retainer 5 engages the annular ridge 3 to restrain the tube 2 from separating from the connector body 4.
A correct connecting procedure for connecting the tube 2 to the connector body 4 includes sequential steps of inserting the tube 2 in the connector body 4 and pressing the retainer 5 into the connector body 4. However, it often occurs that the retainer 5 is pressed into the connector body 4 before the tube 2 is inserted in the connector body 4 as shown in FIG. 9. If the tube 2 is inserted in the connector body 4 after pressing the retainer 5 into the connector body 4, the annular ridge 3 comes into contact with the end 6a of the rib 6 of the retainer 5 and the tube 2 cannot be further inserted in the connector body 4. Consequently, the tube 2 is connected incompletely to the connector body 4. It is difficult to discriminate a condition where the quick connector and the tube 2 are incompletely connected from a condition where the quick connector and the tube 2 are completely connected from appearance. A conventional quick connector is designed such that the tip of the tube 2 is unable to reach O rings 7 and a fluid leaks in a leakage test if the tube 2 and the quick connector are incompletely connected to indicate the incomplete connection of the tube 2 and the quick connector.
A quick connector disclosed in Patent document 3 is designed to enable the recognition of incomplete connection of the quick connector and a tube 2 at a glance. This quick connector includes a complete connection indicating member in addition to a retainer. The complete connection indicating member cannot be easily removed from the quick connector unless the tube 2 is inserted correctly in the quick connector and the retainer is engaged correctly with the tube.
Patent document 1: U.S. Pat. No. 5,542,716
Patent document 2: JP 2002-206683 A
Patent document 3: JP 11-230456 A